The present invention relates to an apparatus for automatically positioning one or more cylindrical cores onto the winding mandrels of a web winding machine, prior to winding a web of material onto each core.
It is known to wind material from a primary roll onto a disposal or rewind core mounted on a winding mandrel with a view to forming a secondary roll (rewind core plus material) of a manageable size. When the secondary roll achieves a predetermined diameter the connection with the primary roll is severed and the secondary roll is removed from the winding mandrel. In order to provide for continuous operation of the web winding machine it is known to provide three or more winding mandrels on a rotatable turret, each of which is equidistantly spaced from its immediate neighbours. As the turret rotates each mandrel in turn passes through respective positions for receiving a rewind core, winding the web of material thereon, severing the connection with the primary roll and removal of the finished secondary roll. In these known machines a human operative places the rewind core onto each mandrel as it arrives at the rewind core receiving position and, likewise, removes the finished secondary roll.
Whilst web winding machines have been described above with reference to a single secondary roll being wound on each winding mandrel in turn, it is more usual for two or more secondary rolls to be wound at a time. Where this occurs accurate positioning and spacing of the rewind cores along the winding mandrel is very important. If the operative fails to position and space the rewind cores accurately on the winding mandrel the webs of material on adjacent secondary rolls may overlap and interleave with each other during winding. Should this occur the secondary rolls must usually be scrapped.
Even assuming that the secondary rolls can be satisfactorily wound on the winding mandrel, problems can arise for the operative between loading the rewind cores and removing them. In this regard, the operative only has a short period of time to remove the completed secondary rolls from a mandrel and then to load that mandrel with the required number of rewind cores. If he fails to act within his period the continuous operation of the machine is interrupted. The smaller the diameter of the finished secondary rolls the shorter the period available to the operative loading each mandrel in turn with rewind cores.
In order to facilitate attachment of the free end of each primary roll to a respective rewind core, the web winding machine may comprise an adhesive applicator which applies a bead of adhesive to each end of each rewind core mounted on the winding mandrel. It will be apparent that where the rewind cores are not accurately positioned on the winding mandrel, these beads of adhesive will be applied to the wrong part of the rewind cores or even onto the winding mandrel itself.